Got an a77 which has the same 2.4Mpixel EVF unit.
Much the same as gbichan, I was initially not that convinced but now I really, really rate it. In good light, you almost don’t notice it’s not an optical finder. It is big and bright and you can overlay lots of exposure info in exactly the same way as you can on an LCD screen (electronic level indicator, histograms, exposure data). You can also see exposure previews showing effects of exposure compensation and distortion and vignetting correction.
Best features, though, are focus peaking with magnification in manual focus mode for PERFECT focusing and the ability to gain-up so that you can see in the dark (albeit with quite a bit of noise) which an OVF cannot do.
It’s a brilliant innovation!